Internal mix catalyst type spray gun and process employing same



INTERNAL MIX CATALYST TYPE SPRAY GUN AND PROCESS EMPLOYING SAME Filed April 11, 1960 Aug. 14, 1962 F. E. COFFMAN 2 Sheets-Sheet 1 U I I G F u 8 M 6 O l 8 3 m 2 M 2 \.1| n 0 Y //XA/ 7- l.- 6 W... 6 2 m o WU 0 m 4 R M 2 o 3 2 5%. 4 5 5 Y I L *4 W 1 I, I WU H LR A INVENTOR Frederick E. Coffmon BY IIGRL CO. FLOCKS ATTORNEY Aug. 14, 1962 F. E. COFFMAN INTERNAL MIX CATALYST TYPE SPRAY GUN AND PROCESS EMPLOYING SAME Filed April 11, 1960 2 Sheets-Sheet 2 flllfdrlflrllmvl IIIIIIIIIIII FIG.4.

INVENTOR Frederick E. Coffmon mm. L0. 7 20 a K5 ATTORNEY United States PatentOfifice 3,649,439 Patented Aug. 14, 1962 3,049,439 INTERNAL MIX CATALYST TYPE SPRAY GUN AND PROCESS EMPLOYING SAME Frederick E. Colfman, Huntingdon, Pa., assignor to Wald Industries, Inc., Huntingdon, Pa., a corporation of Pennsylvania Filed Apr. 11, 1960, Ser. No. 21,351 Claims. (Cl. 117104) The present invention relates to surface coating apparatus and more particularly to apparatus for applying a coating material to surfaces and the like wherein a plurality of materials must be intimately mixed during the spraying operation.

A particular use of the present invention is in the application of markers to roads and highways. Recently, coating compositions have been developed for this use which require the addition of an accelerator to a resin composition during the spraying operation to hasten the polymerization and setting of the resin composition on the base surface. In some cases, more than one additive is required such as dryers, hardeners, catalysts, or fillers.

It has heretofore been proposed to utilize two or more spray guns which spray together the materials to be mixed. It has also been suggested that the materials be mixed together in a tank immediately before spraying and then spraying the pre-mixed material simultaneously. These methods and apparatus have certain drawbacks.

It is therefore an object of the present invention to provide means for spraying a coating material and an additive thereto by pre-mixing the coating material and the additive within the spray gun immediately prior to spraying the mixture therefrom.

Still another object of the present invention is to provide a spraying apparatus for internally mixing within the spray gun a plurality of materials admitted thereto from separate sources of supply.

Still another object of the present invention is to provide spraying apparatus which includes a spray gun for receiving from independent sources a resin paint binder and an accelerator or catalyst, the spray gun ejecting the paint binder and accelerator in a premixed atomized spray onto a base surface.

Still another object of the present invention is to pro- I vide spraying apparatus for road marking which includes a spray gun for receiving from independent sources a resin paint binder, an accelerator or catalyst and small glass spheres, the spray gun ejecting the three materials in an atomized spray to effect a premixed reflective coating on the surface being marked which sets almost instantaneously.

Other objects and the nature and advantages of the instant invention will be apparent from the following description taken in conjunction with the accompanying FIG. 4 is a diagrammatic illustration of a modified form of the apparatus.

Referring to the drawings, the application embodied herein is diagrammatically illustrated in FIG. 1 and includes a spray gun indicated generally as 10. The spray gun 10 is particularly suited for tralfic lane marking and is associated with the conventional equipment required such as a compressor and prime mover, which are adapted to be mounted on a vehicle preferably of the self-propelled type. The Vehicle also carries the source of supply 14 of an accelerator. Additional sources of supply may be included for additional ingredients, such as the small glass beads, etc. as indicated at 15 in FIG. 4.

The apparatus also includes a source of compressed air which serves a two-fold purpose. The compressed air is utilized for atomizing the material, and is also utilized for controlling the supply of the ingredients to the gun by controlling the opening and closing of the supply valves.

The spray gun 10 includes an operating cylinder 16 that controls the flow of the paint binder by raising and lowering a needle valve 18 which seats on a valve seat 29. A piston 22 is connected to the upper end of the needle 18, the piston operating'within the cylinder 16 against a spring 24. A packing seal 26 is located around the needle 18 between the operating cylinder 16 and the main gun body 28. A threaded ring 30 acts to hold the parts of the spray gun together. The main body of the gun 28 as shown in FIG. 1 has two ports 32, 34. Port 32 admits the accelerator mixed with the atomizing air. Port 34 admits the resin binder material. As shown in FIG. 4 the main body 28 has three ports 32, 34 and 35. The port 35 admits glass beads mixed with atomizing air. The air cap 36 is held onto the main gun body 28 by a threaded ring 38. The valve seat 20 is threadedly engaged with the main gun body and is tapered on its outer surface to position the tapered portion 40 of the air cap 36.

The pumps 42 and 44 are shown of the positive displacement type driven by an outside source of rotary or reciprocatory motive power. The pump 42 conveys the accelerator from its source 14 to the port 45 of feed valve 46. The pump 44 conveys the resin binder material from its source 12 to port 34 to supply the resin material directly to the spray gun. The two sources of supply 12 and 14 may be pressurized by the compressed air .or may use a gravity flow supply.

The feed valve 46 has an air operated cylinder, 50 with a piston 52 operating therein against a spring 54 and is connected at its lower end to a needle, 55. The valve body has a through port 56 for the flow "of the atomizing air to the spray gun. The port 45 of the valve body permits the entrance of the accelerator "to the valve, and when actuated, the valve permitsthe flow of accelerator into the port 56 and the stream of atomizing air. The feed valve 46 is actuated by control air which passes through a' valve-58' passing into cylinder port 60 below the piston 52. The control air passing .to actuate both the feed valve 46 for the accelerator and the feed valve 18 for the resin material in the form of the invention shown in FIG. 1 and also for actuating the ,feed valve 46' in the form of the'invention shown in FIG. 4.

The heart of this invention lies in the construction of the air cap 36 of the spray gun 10. When the air cap 36-is mounted on the valve seat 20, a chamber is formed surrounding the valve seat 20 and connected to the port 32 in FIG. 1, and the ports 32 and 35 in FIG. 4. An atomizing chamber 72 is located below the chamber 70 and is in direct connection with the valve seat 20, and also with the chamber 70. Chamber 70 is connected to atomizing chamber 72 by a plurality of holes 74 spaced evenly around the tapered portion of the air cap 36 adjacent to the valve seat 20, and a controlled size ring shaped orifice 76 between the lower end of the outside of the valve seat and the air cap 36. The mixture of atomizing air and accelerator flowing into port 32 passes into chamber 70 and thence through holes 74 and orifice 76 surrounding the valve seat 20. The resin binder which flows into port 34 and thence around needle 18 and between needle 18 and valve seat 20 passes into chamber 72 and is immediately surrounded and sprayed out of the gun by the atomizing air. To improve the mixing of the accelerator and the resin binder in the chamber 72 and to insure uniformity, additional holes 80 are provided between chamber 70 and atomizing chamber 72 which are slanted so that the atomizing air and accelerator passing through the holes 80 are diretced to the center of chamber 72. The atomizing chamber 72 is shown to be diamond-shaped in FIG. 1; however, it also could be spherical as in FIG. 4, or of another suitable shape so that there are no dead spots where the material might accumulate and solidify.

As shown in FIG. 4, the mixture of glass beads and atomizing air flowing into port 35 in FIG. 4 also passes into chamber 70 where it mixes with the accelerator entering through port 32 and the mixture of accelerator, glass beads and atomizing air passes into chamber 70.

In operation, when the valve 58 is actuated, operating air opens the valve 18 and the valve 46 to admit the resin binder through port 34, around needle valve 18 and into chamber 72, and to admit the atomizing air and accelerator through port 32, chamber 70 and holes 74 and 80 into chamber 72. In chamber 72 the atomizing airaccelerator mixture entering through holes 74 around the valve seat 20 picks up the resin binder and conveys it downwardly. The atomizing air-accelerator mixture entering through holes 80 contacts the stream of resin-airaccelerator centrally of the atomizing chamber 72 causing a complete pre-mixing before the mixture is sprayed out of the nozzle onto the base surface to be coated.

When it is desired to pre-mix another material, such as glass beads, along with the accelerator, the apparatus shown in FIG. 4 is utilized and the operation is readily apparent.

An example of the use of a spray gun in accordance with the present invention is in the spraying of a non-slip floor paint where it may be desirable to introduce pumice or other grit into the atomized stream.

.As shown in FIGS. 2 and 4 the valve means 46 and 46' may be embodied as an integral portion of the spray gun body.

A gun shroud 90 is shown in FIG. 3 threadedly engaged to the spray gun surrounding the nozzle. To me vent the catalyzed material mist from solidifying in the top or dome of the shroud 90, a plurality of holes 92 are provided drilled through the outside periphery at the top of the shroud, thereby permitting air to be drawn in thle shroud and prevent the build-up of solidified materla The width of the marker sprayed onto a highway surface is determined by the height of the spray gun from the surface as well as the shape of the nozzle.

When immediate reflectivity of the road marker is desired, a second spray gun, not shown, is carried by the vehicle, positioned to the rear of spray gun 10. Dry glass spheres are ejected in a fan-like pattern onto the surface of the freshly sprayed road marker and become partially embedded therein before the composition completely cures.

It will be obvious to those skilled in the art that various changes may be made without departing from the spirit of the invention and therefore the invention is not limited to what is shown in the drawings and described in the specification but only as indicated in the appended claims.

What is claimed is:

1. In apparatus for applying a coating to a surface by means of an atomizing fluid, a spray gun having a first inlet port, a second inlet port, a first chamber, a mixing chamber, a nozzle at the exit of said mixing chamber, a first source of supply for a material to be sprayed in communication with said first inlet port, a second source of supply including the atomizing fluid and an additive or the material to be sprayed in communication with said second inlet port, a first conduit connecting said first inlet port and said mixing chamber, a second conduit connecting said second inlet port and said first chamber, a first plurality of openings connecting said first chamber and said mixing chamber, said openings being directed towards the central portion of said mixing chamber, and a second plurality of openings immediately surrounding the point of entry of said first conduit into said mixing chamber, said openings connecting said first chamber and said mixing chamber whereby the material being sprayed is intimately mixed with said additive and said atomizing fluid in said mixing chamber prior to being sprayed through said nozzle.

2. Apparatus in accordance with claim 1, including a third inlet port connecting with said first chamber, a third source of supply for a second additive, and a conduit for conducting a portion of said atomizing fluid into communication with said third inlet port, whereby said additives are mixed in said first chamber and are injected into the material to be sprayed in said mixing chamber prior to being sprayed through said nozzle.

3. In apparatus in accordance with claim 1 wherein said mix-ing chamber is hollow and frustro-diamondshaped having upper and lower frustro-conical portions meeting at an expanded central point with the material to be sprayed entering at the top thereof, the nozzle being located at the bottom thereof, and the additiveatomizing air openings directed towards the central portion of said mixing chamber entering at points slightly above the widest portion of said mixing chamber.

4. In apparatus in accordance with claim 1 wherein said mixing chamber is frustro-spherical shaped with the material to be sprayed entering at the top thereof, the nozzle being located at the bottom thereof, and the additive atomizing air openings directed towards the central portion of said mixing chamber entering at points slightly above the widest portion of said mixing chamber.

5. Apparatus for applying a coating to a surface comprising a spray (gun, said spray gun including a first inlet port, a second inlet port, a first chamber, a mixing chamber, a nozzle at the exit of said mixing chamber, a first source of supply for a material to be sprayed in communication with said first inlet port, a first conduit connecting said first inlet port and said mixing chamber, a second source of supply for an additive for the material to be sprayed in communication with said second inlet port, a valve means located between said second source of supply and said second inlet port, said valve means controlling the flow of said additive, a source of atomizing fluid in communication with the exit from said valve means to form a mixture of additive and atomizing fluid entering said second inlet port, a second conduit connecting said second inlet port and said first chamber, a plurality of openings connecting said first chamber and said mixing chamber, said openings being directed towards the central portion of said mixing chamber, and a second plurality of openings immediately surrounding the point of entry of said first conduit into said mixing chamber, said openings connecting said first chamber and said mixing chamber whereby the material being sprayed is intimately mixed with said additive and said atomizing fluid in said mixing chamber prior to being sprayed through said nozzle.

6. Apparatus in accordance with claim 5, including a third inlet port connecting with said first chamber, a

third source of supply for a second additive, and a conduit for conducting a portion of said atomizing fluid into communication with said third inlet port, whereby said additives are mixed in said first chamber and are injected into the material to be sprayed in said mixing chamber prior to being sprayed through said nozzle.

7. In apparatus in accordance with claim 5 wherein a second valve means is located in said first conduit immediately before its entry into said mixing chamber for controlling the flow of material to be sprayed.

8. In apparatus in accordance with claim 5 wherein said mixing chamber is hollow and frustro-diamondshaped having upper and lower frustro-conical portions meeting at an expanded central point with the material to be sprayed entering at the top thereof, the nozzle being located at the bottom thereof, and the addititiveatomizing air openings directed towards the central portion of said mixing chamber entering at points slightly above the widest portion of said mixing chamber.

9. In apparatus in accordance with claim 5 wherein said mixing chamber is frustro-spherical shaped with the material to be sprayed entering at the top thereof, the nozzle being located at the bottom thereof, and the additive-atomizing air openings directed towards the central portion of said mixing chamber entering at points slightly above the Widest portion of said mixing chamber.

10. In a method of applying a marker to a surface, comprising the steps of supplying a first stream of resin paint binder to a spray gun mixing chamber at the top thereof, supplying a second stream of atomizing fluid carrying an accelerator for rapidly curing said resin paint binder to said spray gun, admitting a portion of said second stream to the mixing chamber at the top thereof surrounding said first stream, admitting the balance of said second stream to said mixing chamber at a plurality of points spaced about its upper portion each being directed toward the center of said mixing chamber Whereby said first stream and said second stream are uniformly premixed, and spraying said pro-mixed streams out of the bottom portion of said mixing chamber, said binder curing on said surface into a solid.

References Cited in the file of this patent UNITED STATES PATENTS 1,462,395 Thompson July 17, 1923 1,762,395 Thompson July 17, 1923 2,532,187 Paasche Nov. 28, 1950 2,754,153 Barthod July 1 0, 1956 2,813,751 Barrett Nov. 19, 1957 2,814,751 Barrett Nov. 19, 1957 2,823,143 Upperman Feb. 11, 1958 2,907,527 Cummings Oct. 6, 1959 

10. IN A METHOD OF APPLYING A MARKER TO A SURFACE, COMPRISING THE STEPS OF SUPPLYING A FIRST STREAM OF RESIN PAINT BINDER TO A SPRAY GUN MIXING CHAMBER OF THE TOP THEREOF, SUPPLYING A SECOND STREAM OF ATOMIZING FLUID CARRYING AN ACCELERATOR FOR RAPIDLY CURING SAID RESIN PAINT BINDER TO SAID SPRAY GUN, ADMITTING A PORTION OF SAID SECOND STREAM TO THE MIXING CHAMBER AT THE TOP THEREOF SURROUNDING SAID FIRST STREAM, ADMITTING THE BALANCE OF 